Dynamic viscoelastic properties of diglycidyl ether of bisphenol A (DGEBA) cured with diaminodiphenylmethane (DDM) have been studied. The relaxation spectra of stoichiometric mixtures have been investigated as a function of the casting procedure and the thermal history during curing. Variations on the temperatures of the loss peaks and also on their magnitude have been observed when a solvent was employed to cast the mixtures. These variations have been attributed to the existence of high crosslinked regions formed at the earlier stage of curing inside the overall matrix. The results obtained from mixtures cured with different thermal histories underline the importance of adequate selection of curing conditions in order to obtain the optimum properties for these materials. Differences in crosslink density amongst the mixtures cured at different conditions have been correlated to the extent of reaction obtained by infrared measurements.